Table reflector



June 10, 1930.- CUNE ET AL 1,762,469

TABLE REFLECTOR Filed Sept. 8, 1927 Patented June 10, 1930 UH'E dTATES twan PATENT trier HARRY I. GLINE, OF PHILADELPHIA, PENNSYLVANIA, AND ISIDORE SCHEINBERG AND JOHN G. WATSON, OF BALTIMORE, MARYLAND, ASSIGNORS TO SILVERGLO LAMPS, INCL, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND TABLE REFLECTOR Application filed September 8, 1927. Serial No. 218,253.

This invention relates to improvements in reflectors for electric lamps, and more particularly refers to reflectors which are employed to produce a uniform illumination of a surface.

Reflectors of this type are especially valu able for use on playing tables such as billiard tables, where it is essential for accuracy of the play that the illumination shall be uniform over the whole area of the table; and on the other hand, where it is essential that neither the direct rays of the lamp nor any strong reflected rays shall be thrown into the eyes of the player as he stoops near to the table surface: since such direct and reflected rays would distract the attention of the player and affect his study of the situation. It is furthermore essential with such devices that the illuminating unit should be located well above the top of the table so as not to bar the vision across the table from one side to the other, of a person standing alongside the table: and finally it is desirable that the weight and encumbrance of the unit be reduced to a minimum. a

After considerable experimentation a unit has been produced which responds to these requirements, and has been found in practice to yield excellent results. Such an illuminating unit is shown on the accompanying drawings by way of illustration both as the reflector itself, and in conjunction with the lamp and table surface to indicate the general course of the rays.

In these drawings:

Figure 1 is a diametral section through a reflector, indicating the curvature of the parts.

Fig. 2 is a similar section on a smaller scale, with the lamp in position and indicating the course of the direct and indirect illuminating rays.

On these drawings, the reflector is shown as having the upper head 10 to be engaged by a lamp socket fitting whereby the whole reflector may be supported. The metal forming the upper ring 10 extends integrally in a substantially radial plane surface 11 which acts as a reflector for certain of the rays cast obliquely upward from the lamp bulb 12, which is represented in Fig. 2 as being suspended from the socket 123 at the end of a cord 14. Since in the illustrated form the device is represented as a figure of revolution, it may be considered as generated by the revolution of a line about an axis coinciding with the axis of the lamp. This line passes from the head 10 in the substantially radial or right-angle portion 11 which then bends downward in an arcuate portion 15 which is of substantially half the radius of the fin ished reflector, and finally forms the portion 16 which is almost cylindrical but has a slight outward and downward divergence, and ends with an outward flare 17 joining it to the line portion 18 which formsa cylindrical lower band, and finally has an outward and inward curve to form a head 19 about the stilfeningwireQO. i

The lamp bulb 12 is so located that the source of light has an effective center substantially in the plane of the circle which forms the line of substantial centers ofthe are 15. This circle of centers is likewise separated from the axis by a distance substantially equal to the radius of the are 15 itself, and hence the tangent line portion 11 is of such length.

In operation, a lamp bulb 12 having a frosted bottom, of the so-called half frosted type is inserted in the socket 13 and the device is suspended at a predetermined distance above thesurface to be illuminated. It may be pointed out that, for a billiard table for example, the shade is designed to be suspended at a distance of forty inches from the lower edge of the reflector to the table surface: and for thispurpose the device is made sixteen inches in inside diameter at its lower edge, and seven and one-half inches deep from the lower edge to the lower surface of the substantially radial portion 11; the band 1Sis substantially 1 inches wide: and a 7 5 watt Mazda lamp with frosted bottom is usually employed. a

With these dimensions, the direct illumination (cl) from the lamp bulb 12 is diffused by its frosted bottom and is distributed over the table surface in a proportion which varies inversely as the square of the distance from the effective center of the lamp bulb fiament to the table surface at the particular point, in known manner. To complement this nonuniform illumination, the upward rays from the lamp bulb 12 are caused to be reflected from the surface 11 and from the surface 15: and lateral rays from the lamp bulb are likewise reflected by the surfaces 15 and 16. There therefore exist three types of reflected rays: (1) Rays a reflected to the table surface away from the axis directly fromthe surface 11; (2) rays 6 reflected from the surface 11 or 15 to the surfaces 15, 16 and thence reflected across the axis to illuminate the opposite side of the table; (3) rays 0 reflected from the surfaces 15, 16, 17 directly upon the table, passingoacross the axis. By the particular shape shown and described, these rays are so distributed that more illumination is delivered from the lamp at the edge of the -table by these indirect rays than is delivered along the line of'the axis: and in particular the total indirect illumination complements the direct illumination, and with the conditions of height and diameter set forth, the table surface is given a uniform intensity of illumination through the area covered by the unit.

A further refinement of the device is the ype o efl etingr a e mp y d in the reflector. It is preferred to provide the inside surfaces at 11, ,5,,16and 17 with a coat ing ,ofjhighly reflective material of white color, and usually of an egg-shell matte finish to prevent glare. Thesesurfaces act to produce the illumination indicated above:

while the interior of th "band 18 is coated with alightfblue which cuts down-the appan nten ty 0f the light and is very agree able to the eye of the player, while at the same time delivering from the lamp bulb sufiicient general illumination about the table and above its edge. As the player stoops to sight along his cue, for example, his eye may notice the illuminatjion on this band but this is not i-rritating to him and does not effect e quali y of' iis lay It Wil be n ed tha this downward projection of the cylindrical flange 18 therefore serves several purposes:

to W ai etifieu and suppo ts the m i o y 1 of the reflecter, it limits the path of rays o e the chose co e f istri ti n ;-it pr vides a soft general illumination; and it, hile be ng nt n ly lluminated, es n injure the playerisreyes.

t W ll'be un er o d tha e p ifi dimensions givenabove "are illustrative and calculated forusein combination with one another for the given conditions. The in vention is not -limitedthereto; nor to the P eifie,- li1min ti n of illi rd t ble ut may beemployed other ways where uniform intensity .ofjillumination is required. b sbv eu th r for tha he invention vm y be mo ifi d in a y ays Wi h n the scope fthe append d Claim from the lamp or reflector from encountering the eyes of such standing person, said shade having a diameter approximately onehalf its height above the table and having its reflecting surface of the form of a figure of revolution generated by the movement about the lamp axis of a line starting at a point at substantially one-half the depth of the shade above the predetermined location of the light sourceof the same, said line extending horizontally outwardly from such axis whereby to provide a first primary refleeting surface above the light source to re flect and distribute light rays away from the axis, said line then curving downward toward parallelism with said axis in an arc approximatelyequal in radius to substan tially one-half the depth ofthe shade whereby to form a second primary reflecting surface above the light source to reflect anddistribute rays away from and across the axis, said line then extending downwardly with a slight outward slope and terminating in substantial parallelism with the axis whereby to form a third primary reflecting surface below the light source to reflect and distribute light rays across the axis, said third surface cooperating also with said first surface to reflect and distribute rays therefrom across the axisof the lamp at different angles than thoseofthe primary reflected rays from said third surface, all of said surfaces cooperating to produce a uniformillumination by said lamp of a plane perpendicular to said axis and located a predetermined distance from said light source.

2. An illuminating unit as in claim 1 in which the shade is provided with a lower cylindrical peripheral band of greater diameter than the lower part of said third reflecting surface and joined thereto by an outward flare therefrom whereby to stiffen the shade, said band being internally coated .with a less reflective material of a darker color than the other portions of the interior of the shade whereby-to soften the reflect-ion into the players eyes from such portions of the shade when he stoops to play.

3. An illuminating unit comprising in combination an incandescent electric lamp of the half-frosted type, an inverted cup-like reflecting shade, and means to support said shade with its bottom edge substantially forty inches above the surface to be illuminated, said shade having the form of a figure of revolution about a vertical axis with a diameter of substantially sixteen inches at its lower edge and a depth of substantially one-half of said diameter, said figure being formed by the revolution about said axis of a line extending at a right angle away from said axis and then curving downward on an are having a radius equal to substantially one-half the radius, of the shade and its center at a distance from the axis substantially equal to one-half the radius of the shade, and thence continuing downwardly and outwardly tangent to said arc, said lamp being located with its filament substantially at the level and center of the circle produced by the revolution of said first center about said axis.

4. A shade for an incandescent lamp comprising an inverted cup-like reflecting member having the form of a figure of revolution generated by a line extending away from the axis at a right angle thereto for a distance substantially equal to one half the radius of the lower edge of the shade to provide a plane first reflective surface, then continuing outwardly and downwardly on an arc whose radius is substantially equal to onehalf of the radius of the lower edge of the shade to provide a curved second reflective surface, and thence continuing downwardly and slightly outwardly to provide substantially a slightly conical third reflective surface, and terminating in a portion parallel to the axis whereby to provide a cylindrical lower band, said third reflective surface being joined to said cylindrical band by an outward flare whereby to stiffen the shade, said band being coated interiorly with a less reflective material.

In testimony whereof, we afiix our signatures.

HARRY P. CLINE. ISIDORE SGHEINBERG. JOHN G. WATSON. 

